The correct design is to deploy the application in both data centers, advertise the application prefix from DC1 as a /32, and advertise a broader /24 from DC2. This uses longest-prefix-match behavior to create deterministic primary and backup routing. Cisco routing logic prefers the most specific matching route in the routing table, regardless of administrative distance or metric comparisons among less specific covering routes.
As long as the DC1 /32 is present, traffic for that exact application address follows DC1. If DC1, its edge path, or the /32 advertisement fails, the /32 is withdrawn and the remaining /24 covering route from DC2 provides backup reachability. Advertising the same prefix from both locations may result in load sharing or provider-dependent selection, which does not guarantee DC1 primary behavior. IP SLA could be used in some route-tracking designs, but the clean routing solution tested here is prefix specificity. Reference topics:
longest-prefix match, BGP advertisement, active/standby data center routing, covering routes, route failover.